We’ve reaped phenomenal results in researching the power of giving, and the results may seem counterintuitive to the field of positive psychology.

We’ve known that social connection is the greatest predictor of happiness—measured by how people rate the quality of their lives, what we call “subjective well-being”—in the long term. But we’ve traditionally measured it by how much social connection you’re receiving. Is someone there for you in times of trouble? Do you have a special person you can talk to? Do people ask you to go out for social engagements? Do people do nice things for you or bring you gifts?

To study the other side of the coin, I flipped those questions and asked companies I’ve worked for to use them in surveying their people. The new questions: Are you initiating social engagements? Giving the gifts? Bringing the doughnuts to the office? If someone is having a rough time, are you the person they talk to?

By analyzing the results, we realized that being on the receiving end of social connections wasn’t nearly as powerful as being the giver in relationships. We found that people who are work and life altruists, the givers, are more engaged. The top 25 percent of people who are more altruistic are 40 percent more likely to receive promotions over a two-year span.

They’re happier with their lives and their work. We found that people who are constantly giving to their families and friends are significantly happier than those who are not. When someone feels as if he has to wait for his family to do something nice for him, he’s engaging in deficit thinking. He’s thinking about what he doesn’t have in that moment. Someone else has all the power. But when you become a giver, you return the power back to yourself. So you change from deficit thinking to a growth mindset. Suddenly your brain starts seeing all these opportunities to give, and it causes you to feel greater levels of happiness and lower levels of threat.

Giving can take many forms, and social connection is one of the most important. But this is the holiday season, so let’s also take a moment to talk about gifts.

The most rewarding gifts are the ones you’ve thought about thoroughly and planned for a long time. Even if you spent a lot of money to buy something but you did it at the last minute, you robbed yourself of anticipatory happiness. For instance, last year I went online and created a pillow for my wife, Michelle, which was decorated with a few dates that are important to our family. I knew it was a gift that she would love, and this was three months in advance. I was so excited by how happy it would make her that it was almost torture not to give it to her every day up until Christmas.

She loved it. And that’s important for the happiness of the giver, too, but not as much as you might think.

As a giver, if you get the facial and nonverbal cues that you want—gratitude—your brain immediately lights up, those mirror neurons activate, and you double the recipient’s smile. But if our happiness is contingent on someone else’s emotional response, it makes us unstable. We lose the power.

Sometimes I’ve been excited about a present, but the recipient wasn’t as thrilled about it as I expected. I end up feeling they’re ungrateful, or I don’t feel motivated to do it again in the future. But if I really focus my mental energy on how happy I made myself feel by giving the gift, I control the power in the exchange and am incentivized by continuing to give in the future, regardless of the emotional response.